Jacob Rabinowitz Russ. to N.Y.

I have very little info as both parents and most reletives are deceased.Father was Jacob Rabinowitz b. 1914 in New York City.His fathers name is unknown as well as the mothers.Except the mothers maiden name is Jatzcowitz Ring a bell with anyone?I should mention that Jacob Rabinowitz changed his name(long story)to Jack Renard in the 30's(?)